This guy doesn't even know what basic masterfrost is, and you want him to try to use blood tap properly as DW frost? I don't even use blood tap myself. I'm not convinced it's a performance gain outside of simcraft.

With the amount of magic damage going on in heroic modes and the levels of haste we can get it can happen.

And when it happens with runic empowerment you have a maximum resource state of 6 runes and 100 runic power, and with blood tap you have 6 runes, 100 runic power and an extra 2.4 runes from the blood charges.

It isn't massively relevant, but it's a slight damage increase some of the time.